Replace Traefik with mproxy

[mproxy](https://github.com/kevinmcconnell/mproxy) is a custom minimal
proxy designed specifically for Kamal.

It has two big advantages over Traefik:
1. Imperative deployments - we tell it to switch from container A to
   container B, and it waits for container B to start then switches. No
   need to poll for health checks ourselves or mess around with forcing
   health checks to fail.
2. Support for multiple apps - as much as possible, configuration is
   supplied at runtime by the deploy command, allowing us to have
   multiple apps share an instance of mproxy without conflicting config.

test/integration/accessory_test.rb

@@ -1,6 +1,6 @@
 require_relative "integration_test"
 
-class AccessoryTest < IntegrationTest
+class IntegrationAccessoryTest < IntegrationTest
   test "boot, stop, start, restart, logs, remove" do
     kamal :envify
 

test/integration/app_test.rb

@@ -1,6 +1,6 @@
 require_relative "integration_test"
 
-class AppTest < IntegrationTest
+class IntegrationAppTest < IntegrationTest
   test "stop, start, boot, logs, images, containers, exec, remove" do
     kamal :envify
 

test/integration/docker/deployer/app/.kamal/hooks/post-proxy-reboot

@@ -0,0 +1,3 @@
+#!/bin/sh
+echo "Rebooted proxy on ${KAMAL_HOSTS}"
+mkdir -p /tmp/${TEST_ID} && touch /tmp/${TEST_ID}/post-proxy-reboot

test/integration/docker/deployer/app/.kamal/hooks/post-traefik-reboot

@@ -1,3 +0,0 @@
-#!/bin/sh
-echo "Rebooted Traefik on ${KAMAL_HOSTS}"
-mkdir -p /tmp/${TEST_ID} && touch /tmp/${TEST_ID}/post-traefik-reboot

test/integration/docker/deployer/app/.kamal/hooks/pre-proxy-reboot

@@ -0,0 +1,3 @@
+#!/bin/sh
+echo "Rebooting proxy on ${KAMAL_HOSTS}..."
+mkdir -p /tmp/${TEST_ID} && touch /tmp/${TEST_ID}/pre-proxy-reboot

test/integration/docker/deployer/app/.kamal/hooks/pre-traefik-reboot

@@ -1,3 +0,0 @@
-#!/bin/sh
-echo "Rebooting Traefik on ${KAMAL_HOSTS}..."
-mkdir -p /tmp/${TEST_ID} && touch /tmp/${TEST_ID}/pre-traefik-reboot

test/integration/docker/deployer/app/Dockerfile

@@ -6,4 +6,5 @@ ARG COMMIT_SHA
 RUN echo $COMMIT_SHA > /usr/share/nginx/html/version
 RUN mkdir -p /usr/share/nginx/html/versions && echo "version" > /usr/share/nginx/html/versions/$COMMIT_SHA
 RUN mkdir -p /usr/share/nginx/html/versions && echo "hidden" > /usr/share/nginx/html/versions/.hidden
+RUN echo "Up!" > /usr/share/nginx/html/up
 

test/integration/docker/deployer/app/config/deploy.yml

@@ -21,11 +21,8 @@ builder:
     COMMIT_SHA: <%= `git rev-parse HEAD` %>
 healthcheck:
   cmd: wget -qO- http://localhost > /dev/null || exit 1
-traefik:
-  args:
-    accesslog: true
-    accesslog.format: json
-  image: registry:4443/traefik:v2.10
+proxy:
+  image: registry:4443/dmcbreen/mproxy:latest
 accessories:
   busybox:
     service: custom-busybox
@@ -33,4 +30,4 @@ accessories:
     cmd: sh -c 'echo "Starting busybox..."; trap exit term; while true; do sleep 1; done'
     roles:
       - web
-stop_wait_time: 1
+stop_wait_time: 5

test/integration/docker/deployer/setup.sh

@@ -19,7 +19,7 @@ push_image_to_registry_4443() {
 
 install_kamal
 push_image_to_registry_4443 nginx 1-alpine-slim
-push_image_to_registry_4443 traefik v2.10
+push_image_to_registry_4443 dmcbreen/mproxy latest
 push_image_to_registry_4443 busybox 1.36.0
 
 # .ssh is on a shared volume that persists between runs. Clean it up as the

test/integration/integration_test.rb

@@ -44,10 +44,10 @@ class IntegrationTest < ActiveSupport::TestCase
       deployer_exec(:kamal, *commands, **options)
     end
 
-    def assert_app_is_down
+    def assert_app_is_down(response_code: "503")
       response = app_response
-      debug_response_code(response, "502")
-      assert_equal "502", response.code
+      debug_response_code(response, "503")
+      assert_equal "503", response.code
     end
 
     def assert_app_is_up(version: nil)
@@ -96,8 +96,8 @@ class IntegrationTest < ActiveSupport::TestCase
     def assert_200(response)
       code = response.code
       if code != "200"
-        puts "Got response code #{code}, here are the traefik logs:"
-        kamal :traefik, :logs
+        puts "Got response code #{code}, here are the proxy logs:"
+        kamal :proxy, :logs
         puts "And here are the load balancer logs"
         docker_compose :logs, :load_balancer
         puts "Tried to get the response code again and got #{app_response.code}"
@@ -124,8 +124,8 @@ class IntegrationTest < ActiveSupport::TestCase
     def debug_response_code(app_response, expected_code)
       code = app_response.code
       if code != expected_code
-        puts "Got response code #{code}, here are the traefik logs:"
-        kamal :traefik, :logs
+        puts "Got response code #{code}, here are the proxy logs:"
+        kamal :proxy, :logs
         puts "And here are the load balancer logs"
         docker_compose :logs, :load_balancer
         puts "Tried to get the response code again and got #{app_response.code}"

test/integration/lock_test.rb

@@ -1,6 +1,6 @@
 require_relative "integration_test"
 
-class LockTest < IntegrationTest
+class IntegrationLockTest < IntegrationTest
   test "acquire, release, status" do
     kamal :envify
 

test/integration/main_test.rb

@@ -1,6 +1,6 @@
 require_relative "integration_test"
 
-class MainTest < IntegrationTest
+class IntegrationMainTest < IntegrationTest
   test "envify, deploy, redeploy, rollback, details and audit" do
     kamal :envify
     assert_local_env_file "SECRET_TOKEN=1234"
@@ -9,7 +9,7 @@ class MainTest < IntegrationTest
 
     first_version = latest_app_version
 
-    assert_app_is_down
+    assert_app_is_down response_code: "502"
 
     kamal :deploy
     assert_app_is_up version: first_version
@@ -31,11 +31,11 @@ class MainTest < IntegrationTest
     assert_app_is_up version: first_version
 
     details = kamal :details, capture: true
-    assert_match /Traefik Host: vm1/, details
-    assert_match /Traefik Host: vm2/, details
+    assert_match /Proxy Host: vm1/, details
+    assert_match /Proxy Host: vm2/, details
     assert_match /App Host: vm1/, details
     assert_match /App Host: vm2/, details
-    assert_match /traefik:v2.10/, details
+    assert_match /dmcbreen\/mproxy:latest/, details
     assert_match /registry:4443\/app:#{first_version}/, details
 
     audit = kamal :audit, capture: true
@@ -76,7 +76,7 @@ class MainTest < IntegrationTest
     assert_equal({ user: "root", port: 22, keepalive: true, keepalive_interval: 30, log_level: :fatal }, config[:ssh_options])
     assert_equal({ "multiarch" => false, "args" => { "COMMIT_SHA" => version } }, config[:builder])
     assert_equal [ "--log-opt", "max-size=\"10m\"" ], config[:logging]
-    assert_equal({ "path" => "/up", "port" => 3000, "max_attempts" => 7, "exposed_port" => 3999, "cord"=>"/tmp/kamal-cord", "log_lines" => 50, "cmd"=>"wget -qO- http://localhost > /dev/null || exit 1" }, config[:healthcheck])
+    assert_equal({ "path" => "/up", "port" => 3000, "max_attempts" => 7, "exposed_port" => 3999, "log_lines" => 50, "cmd"=>"wget -qO- http://localhost > /dev/null || exit 1" }, config[:healthcheck])
   end
 
   test "setup and remove" do

test/integration/proxy_test.rb

@@ -0,0 +1,65 @@
+require_relative "integration_test"
+
+class IntegrationProxyTest < IntegrationTest
+  test "boot, reboot, stop, start, restart, logs, remove" do
+    kamal :envify
+
+    kamal :proxy, :boot
+    assert_proxy_running
+
+    output = kamal :proxy, :reboot, capture: true
+    assert_proxy_running
+    assert_hooks_ran "pre-proxy-reboot", "post-proxy-reboot"
+    assert_match /Rebooting proxy on vm1,vm2.../, output
+    assert_match /Rebooted proxy on vm1,vm2/, output
+
+    output = kamal :proxy, :reboot, :"--rolling", capture: true
+    assert_proxy_running
+    assert_hooks_ran "pre-proxy-reboot", "post-proxy-reboot"
+    assert_match /Rebooting proxy on vm1.../, output
+    assert_match /Rebooted proxy on vm1/, output
+    assert_match /Rebooting proxy on vm2.../, output
+    assert_match /Rebooted proxy on vm2/, output
+
+    kamal :proxy, :boot
+    assert_proxy_running
+
+    # Check booting when booted doesn't raise an error
+    kamal :proxy, :stop
+    assert_proxy_not_running
+
+    # Check booting when stopped works
+    kamal :proxy, :boot
+    assert_proxy_running
+
+    kamal :proxy, :stop
+    assert_proxy_not_running
+
+    kamal :proxy, :start
+    assert_proxy_running
+
+    kamal :proxy, :restart
+    assert_proxy_running
+
+    logs = kamal :proxy, :logs, capture: true
+    assert_match %r["level":"INFO","msg":"Server started","http":80,"https":443], logs
+
+    kamal :proxy, :remove
+    assert_proxy_not_running
+
+    kamal :env, :delete
+  end
+
+  private
+    def assert_proxy_running
+      assert_match %r[registry:4443/dmcbreen/mproxy:latest   "mproxy run"], proxy_details
+    end
+
+    def assert_proxy_not_running
+      refute_match %r[registry:4443/dmcbreen/mproxy:latest   "mproxy run"], proxy_details
+    end
+
+    def proxy_details
+      kamal :proxy, :details, capture: true
+    end
+end

test/integration/traefik_test.rb

@@ -1,65 +0,0 @@
-require_relative "integration_test"
-
-class TraefikTest < IntegrationTest
-  test "boot, reboot, stop, start, restart, logs, remove" do
-    kamal :envify
-
-    kamal :traefik, :boot
-    assert_traefik_running
-
-    output = kamal :traefik, :reboot, "-y", capture: true
-    assert_traefik_running
-    assert_hooks_ran "pre-traefik-reboot", "post-traefik-reboot"
-    assert_match /Rebooting Traefik on vm1,vm2.../, output
-    assert_match /Rebooted Traefik on vm1,vm2/, output
-
-    output = kamal :traefik, :reboot, :"--rolling", "-y", capture: true
-    assert_traefik_running
-    assert_hooks_ran "pre-traefik-reboot", "post-traefik-reboot"
-    assert_match /Rebooting Traefik on vm1.../, output
-    assert_match /Rebooted Traefik on vm1/, output
-    assert_match /Rebooting Traefik on vm2.../, output
-    assert_match /Rebooted Traefik on vm2/, output
-
-    kamal :traefik, :boot
-    assert_traefik_running
-
-    # Check booting when booted doesn't raise an error
-    kamal :traefik, :stop
-    assert_traefik_not_running
-
-    # Check booting when stopped works
-    kamal :traefik, :boot
-    assert_traefik_running
-
-    kamal :traefik, :stop
-    assert_traefik_not_running
-
-    kamal :traefik, :start
-    assert_traefik_running
-
-    kamal :traefik, :restart
-    assert_traefik_running
-
-    logs = kamal :traefik, :logs, capture: true
-    assert_match /Traefik version [\d.]+ built on/, logs
-
-    kamal :traefik, :remove
-    assert_traefik_not_running
-
-    kamal :env, :delete
-  end
-
-  private
-    def assert_traefik_running
-      assert_match /traefik:v2.10   "\/entrypoint.sh/, traefik_details
-    end
-
-    def assert_traefik_not_running
-      assert_no_match /traefik:v2.10   "\/entrypoint.sh/, traefik_details
-    end
-
-    def traefik_details
-      kamal :traefik, :details, capture: true
-    end
-end